Pulmonary granulomatous inflammation is observed in a variety of diseases ranging from infectious to those of unknown origin. Management of the pathology accompanying these diseases is often difficult and may require immuno-compromising therapy. This strategy targets the active leukocyte, as end-stage fibrosis is minimally responsive to treatment. While mechanisms by which leukocytes are elicited and activated during lung granuloma development are not fully understood, it is likely that certain chemokines play an important role. This application will focus on the mechanisms whereby monocyte chemoattractant protein-1 (MCP-1) contributes to the initiation and maintenance of pulmonary interstitial inflammation, as MCP-1 has both chemotactic and immunoregulatory properties. Interestingly, MCP-1 appears to block the production of IL-12, while augmenting the production of IL-4. Understanding the cellular and molecular mechanisms by which MCP-1 can participate in the evolution of chronic lung inflammation are the long-term goals of this competing renewal. The hypothesis of this proposal is the following: MCP-1 plays a dual role as a chemoattractant for monocytes and lymphocytes and an immunoregulating cytokine during the development of a immune response with Th2 like characteristics. This hypothesis will be addressed by focusing on the contribution of MCP-1 to the evolution of a Th2 type lung granuloma, as compared to a Th1 response. The following questions will be assessed: 1) What are the contributions of MCP-1 in the elicitation of leukocytes during the evolution of Th1 and Th2 pulmonary lesions? 2) What are the contribution of networks, which include Th1 and Th2 type cytokines, in dictating MCP-1 expression? 3) What are the cellular and molecular mechanisms whereby MCP-1 can regulate the expression of Th1 and Th2 type cytokines? 4) How does the local over expression of either Th1 or Th2 type cytokines, via adenovirus transfection, alter the contribution of MCP-1 to pulmonary granuloma development? 5) How is the evolution of these lesions altered in MCP-1 transgenic versus MCP-1 knockout mice? A number of techniques will be used in this application including: established models of Th1 and Th2 lung granulomatous inflammation using normal, MCP-1 transgenic, and MCP-1 knockout mice; RT- PCR, northern blot, mRNA stability, and in situ hybridization analyses for studying cytokine gene expression; the use of immunochemistry for antigen localization and ELISAs for quantitating cytokines; and gene transfection strategies using adenovirus containing murine cytokine cDNA to assess lung cytokine expression on MCP-1 production.